Abstract: Three tritium labeled 3-quinuclidinyl benzilates were prepared. 3-(G-³H)quinuclidinyl benzilate was prepared by a general exchange with tritiated water in the presence of platium catalyst. 3-quinuclidinyl (benzene-ZH) benzilate was prepared by catalytic tritium exchange of methyl benzilate with tritriated water, followed by ester exchange with 3-quinuclinol. 3-(3(n)-³H) quinuclidinyl benzilate was prepared by catalytic tritiation of quinuclidone, followed by ester exchange with methyl benzilate. The epecific activity were 6.10ci/mmol, O.05ci/mmol and 8.76ci/mmol respectively.